Due to the fact that carbonated spring has good thermal retardation effect, carbonated spring has been utilized in thermal spring bath places. It is essentially considered that the thermal retardation effect of carbonated spring is resulted from the dilatation effect of peripheral blood vessels containing carbonic acid gas, which improves the body environment.
In addition, while carbonic acid gas enters into the body through skin, the capillary bed grows and dilates, and whereby improves the blood circulation of skin. Therefore, good therapeutic effect to degenerated pathological changes of organs and peripheral circulation blockage will be obtained.
Up to now, many articles for the effect of carbonated spring have been published (e.g., see non-patent document 1 and non-patent document 2).
As indicated in non-patent document 1, in the repetitive observations by thermal spring doctors in early stage for major direct effects of carbonated spring, Bode of Bad Nauheim observed hyperemic, velutinous, and ruddy skin (1845); Piderit (1836) and Beneke (1859) stated relaxative sense when in carbon dioxide bath and ruddy skin on the bathed part; Goldschieider discussed in 1911 that the ruddy skin stimulated by carbonic acid was possibly caused by movement of blood vessels.
In addition, as indicated in above articles, two impressing direct effects of carbonic acid bath were observed. One effect is the numerous water vapor bubbles on the skin; the other one is ruddy skin (according to Usui's Ischemic Demarcation theory, the immersed part can be distinguished apparently from the non-immersed part). The water vapor bubbles are numerous carbonated water bubbles, which contact the skin closely and act as “gas brush”.
Furthermore, as indicated in non-patent document 2, the minimum concentration of carbonic acid gas required for therapy is 400 mg; however, as indicated in non-patent document 1, ruddy skin occurs when the concentration of carbonic acid gas reaches 400 mg.
Since carbonated spring has such good effects, many researches have been developed to produce artificial carbonated spring. For example, one method was disclosed in patent document 1.
The process for producing carbonated spring disclosed in patent document 1 comprises supplying warm water to a carbonic acid gas dissolver with gas dissipation device, releasing the carbonic acid gas as bubbles by utilizing the gas dissipation device immersed in warm water and dissolving the bubbles in the warm water, so as to produce carbonated spring. Wherein, after the carbonic acid gas is dissolved in the warm water in said carbonic acid gas dissolver under pressure, the obtained carbonated spring is sent to a gas separator to reduce the pressure to atmospheric pressure, the volatilized carbonic acid gas from the carbonated spring is introduced into a compressor for recovery by the above gas separator, and the recovered carbonic acid gas is introduced into the above carbonic acid gas dissolver and dissolved in the warm water.
However, as for the process for producing carbonated spring disclosed in patent document 1, a gas dissipation device is required. The gas dissipation device has a porous part, from which the carbonic acid gas forms a large amount of bubbles and is dissolved in warm water.
In addition, other known gas dissipation devices include a device with a hollow linear membrane assembly designed to enclose a perforated tube with front part blocked; wherein, the warm water flowing into the perforated tube flows out from the holes on the perforated tube and contacts with the hollow linear membrane, so that the carbonic acid gas injected from the guide port through the hollow part of the hollow linear membrane is dissolved in the warm water.
However, small particles such as impurities in the warm water may block the porous part of the gas dissipation device or the hollow linear membrane. As a result, the gas dissipation device has to be cleaned or replaced frequently, resulting in huge time waste.
Furthermore, since such machines as a carbonic acid gas bomb, a gas separator, and a compressor are required, the apparatus itself is large in size and high in cost.
In addition, since the conventional process for producing carbonated spring employed a carbonic acid gas bomb to dissolve the pressurized carbonic acid gas in water, the carbonic acid gas undissolved in water was directly released to the atmosphere uselessly, which deviated from the tenet of reducing carbonic acid gas in recent years, and caused adverse effect to the global environment.
A known process for producing carbonic acid gas in aqueous solution without the use of a carbonic acid gas bomb was to utilize bath preparations comprising a carbonic acid gas generator which is composed of carbonate and acid (e.g., see patent document 2).
Patent document 1: Japanese Unexamined Patent Publication No. H11-192421
Patent document 2: Japanese Unexamined Patent Publication No. 2005-97238
Non-patent document 1: K. L. Schmid., Carbonated Bath (Carbonated Spring), Journal of Artificial Carbonated Spring Research Society, 1998, 1(1): 005˜009.
Non-patent document 2: B. Hartman, M. Pittler, B. Drews, Carbon Dioxide Thermal Spring Recuperation for Arteriole Blockage Patients: Physiology and Clinic, Journal of Artificial Carbonated Spring Research Society, 1998, 1(1): 010-016.